For example, from the document U.S. Pat. No. 3,771,423 a pivot-pin stabilizing device for a radial piston pump or a radial piston motor is known. The stabilizing device comprises an endplate on the housing which attaches the pivot-pin bearing block. Furthermore, a mechanism for adjusting the position of the pivot-pin, relative to the housing, is provided, this mechanism being arranged on the pivot-pin bearing block. By means of the said mechanism the position of the pivot-pin can be adjusted manually.
Moreover, from automotive technology it is known that hydrostatic motors of radial piston design are used in transmissions. The used motors have an arrangement for eccentric adjustment with which the displacement volume can be set within specified limits. The eccentric adjustment takes place on an eccentric element supported on the inside, which can be positioned by means of an adjusting device in the direction of minimum and maximum eccentricity. The adjustment takes place by means of the pressure medium supply of the motor, which is connected to the adjusting device by a changeover valve. For this, a volume flow of the pressure medium is set which corresponds to the desired adjustment. When magnetic seat valves are used for controlling the motor, these are alternately switched on and off. The pressure medium is held in during adjustment and only switched through when, because of leakages, the actual displacement volume differs from the desired displacement volume or when it requires adjustment. However, continuous adjustment is not possible with the known arrangement.
Furthermore, the disadvantage arises that the force vector resulting from the working pistons of the motor, which acts upon the eccentric element because of external loads, is orientated in the rotation direction tangentially to the eccentricity. Because of this, a component thereof acts in the direction of maximum or higher, or minimum or lower displacement volume or displacement volume flow. This is opposed by frictional forces and the supporting forces of the adjusting device. In the case of a motor with five working pistons, due to the external loads, the adjusting device is loaded and unloaded in each direction ten times during a single revolution of the motor by virtue of the system. But since only one side of the adjusting device is supplied with pressure medium, the eccentric element shifts and an undesired tendency to vibrate occurs in the system. Moreover, with the known arrangement the displacement volume cannot be regulated reliably.